package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Autowired
    private StringRedisTemplate redisTemplate;
    /**
     *  缓存穿透
     */

    @Autowired
    private CacheClient cacheClient;


    @Override
    public Result queryShopById(Long id) {
      // 缓存穿透 (使用redis封装的工具类)
      // Shop shop = cacheClient.queryWithPathThrough(RedisConstants.CACHE_SHOP_KEY , id,Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.SECONDS);
        // 互斥锁解决缓存击穿
        // Shop = queryWithMutex(id);
        Shop shop = cacheClient.queryWithLogicExpire(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.SECONDS);
        System.out.println(shop);
        if (shop == null){
            System.out.println("查询数据库");
            return Result.fail("商铺不存在");

        }
      // 返回
      return Result.ok(shop);
    }


    // 线程池
    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);

    /**
     *   缓存逻辑过期
      */

 /*   private Shop queryWithLogicExpire(Long id){
        // 1.从redis中查询缓存
        String shopJson = redisTemplate.opsForValue().get("cache:shop:" + id);
        // 2.判断缓存是否存在
        if (StrUtil.isBlank(shopJson)){
            // 3.不存在，直接返回空
            return null;
        }

        // 4.命中，先把json系列化为对象
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        // json Object
        Shop shop = JSONUtil.toBean( (JSONObject)redisData.getData(), Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();
        // 5.判断是否过期
        if(expireTime.isAfter(LocalDateTime.now())){
            // 5.1. 未过期，直接返回
            return shop;
        }

        // 5.2. 已过期，缓存创建
        // 6.缓存重建
        // 6.1. 获取互斥锁
        String lockKey = LOCK_SHOP_KEY + id;
        boolean isLock = tryLock(lockKey);
        // 6.2. 判断获取是否成功
        if(isLock){
            // TODO 6.3. 成功，开启独立线程。实现缓存重建 (用线程池去做)
            CACHE_REBUILD_EXECUTOR.submit(()->{
                // 测试时候设置成30s
                // 创建缓存
                try {
                    this.saveShop2Redis(id, 20L);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }finally {
                    // 释放锁
                    unlock(lockKey);
                }


            });
        }

        // 6.4. 失败，直接返回商铺信息
        return shop;
    }*/


    // 缓存击穿（互斥锁）
  /*  private Shop queryWithMutex(Long id){
        // 1.从redis中查询缓存
        String shopJson = redisTemplate.opsForValue().get("cache:shop:" + id);
        // 2.判断缓存是否存在
        if (StrUtil.isNotBlank(shopJson)){
            // 3.存在，直接返回缓存
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        // 判断命中的shop是否为空值
        if (shopJson != null){
            // 返回一个错误信息
            return null;
        }
        //  4.开始实现缓存创建
        //  4.1.获取互斥锁
        String lockKey = "lock:shop:" + id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey);
            //  4.2.判断是否获取到锁
            if (!isLock){
                //  4.3. 失败则休眠，重试
                Thread.sleep(50);
                return queryWithMutex(id);
            }
            //  4.4. 成功则继续执行

            shop = getById(id);
            // 模拟休眠创建
            Thread.sleep(200);
            // 5.不存在
            if (shop == null){
                // 将空值写入redis缓存，防止缓存穿透
                redisTemplate.opsForValue().set("cache:shop:" + id, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
                // 返回一个错误信息
                return null;
            }
            // 6.存在，写入redis缓存
            redisTemplate.opsForValue().set("cache:shop:" + id, JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
            // 7.释放互斥锁
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }finally {
            unlock(lockKey);
        }
        // 8.返回结果
        return shop;
    }*/

    // 缓存穿透
   /* private Shop queryWithPathThrough(Long id){
        // 1.从redis中查询缓存
        String shopJson = redisTemplate.opsForValue().get("cache:shop:" + id);
        // 2.判断缓存是否存在
        if (StrUtil.isNotBlank(shopJson)){
            // 3.存在，直接返回缓存
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        // 判断命中的shop是否为空值
        if (shopJson != null){
            // 返回一个错误信息
            return null;
        }
        // 4.不存在，查询数据库
        Shop shop = this.getById(id);
        // 5.不存在
        if (shop == null){
            // 将空值写入redis缓存，防止缓存穿透
            redisTemplate.opsForValue().set("cache:shop:" + id, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
            // 返回一个错误信息
            return null;
        }
        // 6.存在，写入redis缓存
        redisTemplate.opsForValue().set("cache:shop:" + id, JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        // 7.返回结果
        return shop;
    }*/

    /**
     * 获取锁
     */
  /*  private boolean tryLock (String key){
        Boolean flag = redisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        // 直接返回flag，会拆箱，会出现空指针异常
        return BooleanUtil.isTrue(flag);
    }*/
    /*
      释放锁
     */
   /* private void unlock (String key){
        redisTemplate.delete(key);
    }*/
    /**
     * 测试redis缓存方法(数据预热)
     */
    public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException {
        // 1.查询店铺数据
        Shop shop = getById(id);
        Thread.sleep(200);
        // 2.封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        // 3.写入redis
        redisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(redisData));
    }

    /**
     * 更新商铺信息
     * @return result
     */
    @Override
    @Transactional  // 开启事务, 保证数据一致性
    public Result update(Shop shop) {
        // 判断id是否为空
        if (shop.getId() == null){
            return Result.fail("商铺id不能为空");
        }
        // 1.更新数据库
        this.updateById(shop);
        // 2.删除缓存
        redisTemplate.delete("cache:shop:" + shop.getId());
        // 3.返回结果
        return Result.ok();
    }

    /**
     * 根据类型查询商铺(而且分页，还有坐标)
     * @param typeId
     * @param current
     * @param x
     * @param y
     * @return
     */
    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        // 1. 是否需要按照坐标查询
        if (x == null || y == null){
            // 不需要，根据类型分页查询
            Page<Shop> page =query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
        // 2. 计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        // 3. 查询redis，按照距离排序，分页 结果：shopId、distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = redisTemplate.opsForGeo() // 可以选择圆心或者地理坐标 还有半径
                .search(key, GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoRadiusCommandArgs.newGeoRadiusArgs().includeDistance()
                                .limit(end));// 5000m，还要手动截取

        if (results == null){
            return Result.ok(Collections.emptyList());
        }
        // 4. 解析出ID
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        // 4.1 截取分页数据
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        // 跳跃时候会出空指针，要判断
        if (list.size() <= from){
            // 没有下一页了
            return Result.ok(Collections.emptyList());
        }
        list.stream().skip(from).forEach(result -> {
            // 4.2 解析出shopId
                    String shopIdStr = result.getContent().getName();
                    ids.add(Long.valueOf(shopIdStr));
             // 4.3 距离
                Distance distance = result.getDistance();
                distanceMap.put(shopIdStr, distance);
                });
        // 5. 根据id查询shop
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id, " + StrUtil.join(",", ids) + "))").list();
        shops.forEach(shop -> {
            // 5.1 设置距离
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        });
        // 6. 返回结果
        return Result.ok(shops);
    }
}
